You can either solder them together properly with a metal strip on the front, or just try positioning the metal correctly inside the case with the cells.
你可以使用前面的金属条将他们焊在一起，或者只是定位好电池盒里面的电池单元的金属条。
2
For each wire, strip off enough insulation that you can solder the wire along the whole length of the trace, since the trace alone is not heavy enough to carry the full motor current.